Were it not for a giant technological leap forward taken two years ago, the City of Edmonton’s Assessment and Taxation Branch’s assessment team would be much larger and more costly to taxpayers.

The staff complement – including assessors, taxation system operators and customer service personnel – has not increased since 2011.

“And because of the innovative computer technology we’re using now, our staff numbers will likely remain at that same level for three or four more years,” says Ron Norton, the branch’s applications manager, “despite the fact that every year, billions of dollars of new assessments and tens of millions in tax revenue are added to our system.”

The technology is called Pictometry, and it combines aerial photography with a very sophisticated computer application.

Every year in May, an airplane equipped with a multi-camera array flies an intricate flight path over the city at a cost of just $200,000. Each sweep captures high-resolution images of what’s below, as well as what’s in a wide swath on all sides of the plane.

“On board the plane,” says Ron, “there’s a powerful computer that crunches all those straight- down and multi-angle views of each property, matching them with GIS coordinates of property lines, producing a top view and 360 degrees of side views.”

This means that instead of getting in their vehicles, driving by to inspect a property that’s been developed or updated, or actually walking onto the site and measuring the developed area – a process taking at least 12 to 25 minutes (depending on whether measurements are required) plus travel time – assessors can do it in far less time using the aerial images.

Images taken annually show the new buildings that were built on previouslyundeveloped land. The Pictometry application calculates the building’s square footage, the firststage in the City’s property assessment process.

Supervisor of land applications, Alanna Young, says the Pictometry application compares images taken in different years on the same computer screen, so assessors can easily see the differences.

“And assessors can use the program to calculate and compare between years various heights, distances and developed areas. The program even calculates the pitch on a roof.”

She says the program is managed by the Taxation and Assessment Branch but is shared with many other areas of the city, including police, fire rescue, Sustainable Development, Transportation and the emergency operations centre.

“During emergencies, Pictometry has been used to figure out better angles to address many kinds of situations. First responders appreciate Pictometry’s ability to let them see potential hazards around each site,” says Alanna.

Fire Rescue Services uses the program to study access to buildings, spot obstacles and measure distances between buildings and houses. Police also use it to study points of egress.

After buying the software in 2013, Ron’s group also purchased an add-on called Change Finder.

“It’s a web-based program that enables us to automatically screen all our images from different years, looking for differences between years,” says Alanna.

“We can isolate those screens down to specific neighbourhoods, to properties that underwent more than a certain percentage of change in developed area, and much more.”

One other advantage of the system is that it spots improvements made by people who build without City permits. In one case, a $1.7 million home was flagged because the owners had built a pool deck on adjacent City property and removed trees at the top of a ravine to create a large back yard. All told, they had illegally developed 11,000 square feet of City property!

As more assessors, and employees across the City, are trained and comfortable using Pictometry, its value to the City has increased. In 2015, the program has already been used to conduct 2,000 assessment inspections, the same number as for all of 2014.

Ron Norton and Alanna Young are the brains behind the operation of the newaerial imagery technology that has allowed the City of Edmonton’s assessment team to keep upwith massive property growth in the city.